How to view what the hard drive is doing?

Hi,

Often when I'm just sitting there reading or doing something that's not
bothering the hard drive, or right after it has booted up but I haven't started
using it yet, I can hear the hard drive crank up and start making it's busy
noises when it seems like there should be nothing for it to do. Is there a way
to view what it IS doing? If so, can we tell if it's a virus or malware or
something, and find out where they are so we can try to get rid of them?

Thanks!
P